The present invention relates to microscope devices and more particularly to objective lens assemblies for use in visually inspecting small-sized parts.
It is frequently desirable to visually inspect small-sized articles of manufacture having parts with substantial depth dimensions such as small diameter bore holes. Traditionally, microscopes having conventional lens systems adapted for viewing slides of specimens have been used to inspect parts which are too small to be clearly viewed by the naked eye. However, such microscopes generally have a very shallow fields at the object plane. Consequently, if the part to be inspected has any significant depth dimensions associated with its features the microscope must be repeatedly refocused in order for the user to be able to examine the entire part. Refocusing takes time and is tiring on the eyes of the user. Further, these microscopes generally do not provide for adequate surface illumination of the part being inspected which makes the inspection of contoured and recessed surfaces even more difficult.
The present invention provides an objective lens assembly which features substantial depth of field at the object plane so that parts can be easily viewed with clarity throughout their depth with a minimum amount of refocusing. Further, the present invention provides a lens assembly which efficiently furnishes illumination to the object being inspected and which is compact in design and is adaptable to be fitted on most conventional microscope bodies.